Smoke Test

The Smoke Test node is the honest one in the pack. It does exactly one thing: it takes the string in its text input (default "hello") and hands it back unchanged. No timer, no secret settings, no hidden mode - the mode dropdown has a single option, echo, because there's nothing else to choose. If you're looking for a tool to build workflows around, move on; this node is a verification device, not a utility.

So why does it exist? Utility-MegaPack is an eight-node pack where every other node is a one-dropdown-does-175-jobs beast. When something that ambitious fails to appear in your node list, you want to know whether the pack itself loaded or whether a deeper dependency broke the import. Drop a Smoke Test on the canvas, type anything, run it, and check the output. If you get your string back, the registration pipeline worked and every other UtilMegaPack_* node should be sitting under the Utility-MegaPack/ menu. The pack even ships a ready-made workflows/01_smoketest.json you can just drag in.

How it works

Under the hood it's the same skeleton as every node in the pack: an operation registry, a process method that dispatches on mode, and a single output. The echo operation is the smallest registered op in the whole codebase - its entire logic is return (text,). If you're poking at how the pack's op system works, this is the cleanest example to read.

The one output socket is text (a STRING), and the one meaningful input is text. Set it, run it, see it. There's also a theme widget, shared across the whole pack - cosmetic only.

Installing it

Smoke Test ships with the pack, so installing the pack installs the node:

cd ComfyUI/custom_nodes
git clone https://github.com/IxMxAMAR/ComfyUI-Utility-MegaPack

Restart ComfyUI, or use ComfyUI Manager and search "Utility-MegaPack". Dependencies are modest (numpy, Pillow, requests, simpleeval, Jinja2, PyYAML, cryptography - no model downloads, nothing exotic). It's on the ComfyUI Registry too, under publisher ixmxamar.

Where people get tripped up

Honestly, this node has no sharp edges because it has no functionality to lose. The one thing worth knowing: it's not a passthrough for building real graphs. Some people grab it thinking "echo" means "a text node," and then wonder why they'd want a node that does nothing. That's the point - it's the pack's "did I install this correctly?" button, and once you've confirmed the pack loads, delete it and get on with your life.